Laptop all my lights will go on but there no windows it is a black screen

As above

and make sure no floppys, cd's, memory sticks, wirelesss cards etc plugged in - just power cable

Hello,
Have you made any hardware changes or has there been any event after which it had this problem?
If not, I would start with replacing memory, or if there are two pieces installed, take 1 out try the other, first in 1 slot then the other, then switch to the second piece and rotate. If you have access to known good memory, try that instead.
Hook up to an external monitor and boot up the laptop. If there's an image on the external, then we've got an lcd problem, most likely the inverter.
Other than that, try using only the ac adapter (take the battery out).
If none of these work, weneed to do more technical changes, such as replacing the inverter, etc.
Good luck